What dark matter (DM) is made of is one of the greatest mysteries in
contemporary particle physics, astrophysics, and cosmology. Although
its nature, such as mass and interaction with other particles, is
unknown, weakly interacting massive particles (WIMPs) are one of the
most popular DM candidates. In the WIMP hypothesis, the current
abundance of DM measured by the Planck
Collaboration [1]} is explained by the thermal
freeze-out scenario in the early Universe. This means that the WIMP
DM possibly annihilates into the standard-model (SM) particles, which
may be detected as high-energy messengers such as gamma rays on the
Earth.
